As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB LEFT AIR CONDITIONING PACK OVERHEATED AND TRIPPED OFF. RIGHT PACK ON PLACARD. RETURNED TO JFK AND LANDED WITHOUT INCIDENT. REPLACED LEFT PACK ALTITUDE SWITCH, COMPRESSOR OUTLET SENSOR AND COMPRESSOR OVER TEMPERATURE SWITCH PART NUMBER 6411371. ALSO REPLACED LEFT PACK LOW LIMIT VALVE. SYSTEM GROUND CHECKED NORMAL OPERATION.